The present invention relates to automatic sorting of pieces of money or similar pieces as a function of their diameter and the diameter can either be that of the pieces to be sorted, as in the case when the pieces are round or simply that of a circle inscribed in the pieces if the pieces are polygonal. More particularly the present invention relates to such a sorter comprising means for bringing pieces generally flat and one at a time, onto the top of a disk which is rotated and which has, on the one hand, a peripheral curb so that the pieces which, under centrifugal force, tend to leave the center of the disk come into edge contact with the curb, and, on the other hand, has at least one circular groove coaxial with the curb and situated at a distance with respect to the curb such that at least the pieces of a certain diameter have their edges, diametrically opposed to those bearing on the curb, overhanging the groove. At least one fixed finger enters the groove so that its forward extremity engages under the overhanging edges of the pieces which pieces, moved by the disk and guided by the top of the finger, are raised and then ejected from the curb by the kinetic forces that the pieces have absorbed.
On the top of the disk there is a circular band adjacent the curb which is usually called a sorting track or selective removal track. This circular band extends radially towards the center of the disk on a path at least slightly greater than the diameter of the largest of the pieces to be sorted. Further, in view of the circular grooves in the disk, this track is in fact formed of several coaxial track portions.
In all the sorters, of the above type, known at the present time, and as shown in U.S. Pat. No. 2,906,276 of Sept. 29, 1959, when they are seen in axial cross-section, these portions of track are all situated on the same straight line. This is true when the disk has a flat track or slightly truncated track and this is also well known. Further, in these sorters, nothing prevents a slight return of the pieces toward the center and the raising of pieces by a finger other than that corresponding to their diameter resulting in a sorting error this return occuring during normal use as by rebounding on the curb or by slow speed or by a stoppage by an exterior intervention.
On the other hand, since the grooves receive the forward end of at least a fixed finger and with play and since each finger should be sufficiently thick to offer the desired resistance, each groove is necessarily relatively wide, notably with respect to the small diameter of certain pieces.
The forward part of the pieces, that is their part turned toward the curb, obviously arrive at a precise moment overhanging this wide groove. At this moment the trajectory of the piece and particularly if it is a piece of small diameter, can, by the play of the weight and also by the resistance to the sliding of the piece on the track, be deflected lightly inwardly.
The portion of the track following the groove being at the same level as the portion which precedes it, it follows then that because of the very small inflection of its trajectory, a piece comes into engagement on the top of the lateral external face of the groove without being able to move directly to the curb. This results in a disturbance of the arrangement of the pieces and a sorting error.